The present invention relates generally to gas turbine engines, and, more specifically, to seals therein.
A gas turbine engine is an assembly of various stator and rotor components which require various types of seals to prevent undesirable leakage of either the hot combustion gases therein or compressed air.
Axially adjoining stator components typically use a ring seal compressed axially therebetween. The ring seal may be a complete 360.degree. member, or it may be circumferentially split at one location for eliminating hoop loads and stresses therein. The split seal is radially elastic so that it may freely expand with an adjoining stator component without hoop restraint or stress therefrom. Ring seals are also axially elastic so that they may be initially axially compressed between the adjoining components for effecting a seal therebetween.
Ring seals may have various transverse cross-sectional configurations such as E-seals or W-seals for example. These shapes provide the required axial flexibility for effecting good seals around the circumference of the seal ring. However, the circumferential split interrupts the ring to form a gap which is a leakage site, although small.
Another version of the ring seal includes a circumferential segment which spans the circumferential gap to reduce or eliminate leakage thereat. Since this slip-seal includes two components, it is correspondingly more complex and expensive to manufacture. The seal segment must be suitably attached to the seal ring to span the circumferentially gap at all times. The segment is typically attached to the ring by welding which further adds to the design complexity and cost, and introduces corresponding heat affected zones. The welded joints are necessarily stress risers which must be accommodated for preventing excessive stress thereat which would undesirably reduce the life of the slip seal.
Accordingly, it is desired to improve slip seals for eliminating welding or other mechanical stress risers, and otherwise simplifying the design and manufacture thereof.